Consistency in language part of the documentation

Made documentation more inline with other parts of the documentation (regarding the way e.g. filenames are presented)
Corrected some spelling errors
Corrected the warning in the language.doc by placing ta reference to the files from which language.doc is generated
Corrected the color for the languages that are still v1.4.6 (language name now also red  in stead of a pink background, was confusing with languages that were 1.5 / 1.6 compatible)